Compass for aircraft



Feb. 5, 1929.

P. ESCALLIER COMPASS FOR AIRCRAFT Filed Dec. 9, 1925 f2 Sheets-Sheet L7UL034 Feb. 5, 1929.

' P. ESCALLEER COMPSS FOR IRCRAFT` Filed Dec. 9, 1925 2 sheets-shew EM/aida' Patented Feb. 5, 1929.

UNITED STATF arman risorsa, or razon, runnen.

@canvass 'rois i.:

Application niet lieceniber 9, 1925, Serial No@ ltt, and in France December t8, 1924.

Errors ot directiona very citen the cause of the loss ot many aircraft forced to land after unsuccessfully trying to identify the region l over which they are flying, are caused almost eliminates the reading of the angle of direc-4 tion, to avoid said errors associated with this reading, and enables the pilot in charge of the v airplane control to spend but little time with gli) the compass.

rlhe instrument consists essentially'in addl ing inside4 the compass cup or bowl, a crown of a certain width and placed at the level of the compass card.

@n the card is partly drawn in black, schematically, an airplanewith. the wing tips and tail drawn on the crown.

'llhe cup or bowl is movable around a vertical axis and so can revolve around the card withthe crown attached to it. rllhe card now bears no graduation but only the schematic drawing ci'u the airplane and also indications The movable cup or bowl has attached to its upper part a scale graduated from left to right.

Finally, the guide line 'is outside and is sup- `ported by the pan or trame into which thel A cup 3 is placed a border graduated clockwise Y movable cup or bowl revolves.

Although the drawing chosen is `of an airplane it could be replaced by any other figure,

but experience has proved' that such a drawing is perfectly suited because the shape oit an airplane gives tour` natural points impossible to confuse among'themselves; furthermore said airplane is directed to a point that is north, a inost excellent base of orienta' The following description wi h appended drawing as an example will clear y and fully illustrate the way this invention is realize Figure l represents a vertical section of a compass according to the invention;

Figure la is an elevation, partly in section; Figure 2 is a top or plan view; Figure 3 is a detail elevation showing how the index representing the guide line is attached to the trame;

Figures d and 5 represent respectively a cross section view and top view of a modil lied construction;

Figures 6, 6, 7 and 7- are diagrams to explain the working of compass;

Figures 8 and 9 show attachment-:of lub-` bers line.

As seen in Figures l, la and 2 an outside bowl l serves as a frame and carries the guide line 2 and driving' mechanism of movable bowl 3. 'lhisl movement is attained by a worm 4 driving a gear attached to inside bowl 3, or by any'oth'er means.

Ilhe inside bowl 3 is very nearly the same as those -used at present. A small screw 30 in bowl 1 engages in a circular notchl in the cup 0r bowl 8 to prevent said bowl 3 from coming out.

pass card (i is a crown 7 securely attached thereto. llhe crown may be omitted at places where there is no marking.v A i Finally, on the compass cardz and crown,

`a black airplane 8 is drawn so that the wing tips, nose and'tail are. on the crown. This airplane is seen complete only when the graduations on the border placed in i'ront of the guide line correspond 4to the aircratts til) inside the bowl ve and imi with the omf course; in any other positionythe wings, tai-l and nose are disaligned from thel body portion.

@n the black` surface ol said airplane,

luminous lines 9 (for night dying) are e placed to permitof an`exact adjustment of the gure.\ @n the upper part oi movable from 0 1:03600 or from 0 to 400 grades or in quadrants. This border bears small rectangles for the inscription of'resid'ual deviations. s

'lhe outside bowll 1 constitutes, strictly speaking, the frame of said movable cup or lbowl 3. lt is composed of n (a) ln the lower part, a de ression ll which receives a journalA l2 on t e movable cup., .l e J vOn the wall,an opening used to admit craft (not shown).

The worm 41s automatically locked in any 105 c position. -Whatever vibrations may be .applied to the movable bowl,l the position cannot vary on account of the one-way movement of the system and lockingof worm by means of a ratchet 14 conveniently placed at on the worm shaft and pressed against a stop 17 b means of a spring 16.

The e line is constituted b an`inclex 2. Its ase 20 bears graduations fiom minus to plus 30 degrees, permitting anexact adjustment of said guide line and correction of declination as explained further in the text.

Two headless screws 18 and 19 slidin in a slot in the base 2O guide said base'w en moved for adjustment purposes.

A lockin screw 21 is used for locking pur oses w en'the ad'ustment is completed. l e aircraft 8 is irawn on the `card in such a way that when the line 0180 of the border is oriented at the letters N and S of the crown, said aircraft is seen com'- plete, all the parts of the crown being then 1n proper relation. It is to be remarked that when4 the plane is seen complete, the course is exact] N S but the win s do not indicate W they are purpose y set upwardly from the center` to prevent the possi ility of erroneous flying which might easily happen if said aircraft were shaped as a per ect cross.

The spaces 22 and 23 on the crown 7 and card 6 respectively between the northward and westward parts of the plane are colored,

` red for example, and in the space 22twov letters are laced that can be read inboth directons; on the north side and L on thewest side. These will be explained later.

Aside from -che schematic drawing, the letters N S W E may be added on the compass card, although they may be dispensed with'. The only recaution to take is that the line 0,-180 o the border coincides withthe line N S, i. e., along the longitudinal axis of the conTipass e airship 1n fllght, will be on the right aircraft body drawn on the crown.

Figures 4 and 5 show a modified construction. Bowl 3 is movable by means of gear 2t and pinion 25 with locking means similar to that already described for the worm.

' The remainder of the compass is similar to Figures 1 and 2.

The operationand use of the vcompass are follows: c

Th ilot finds-his cnurse on the map. He then akes the necessar .modificationa He adds or subtracts the dri if necessary. Havmg the angle of direction on the compass, the pilot turns theilmurled head attached vtoworm to move the border 10 until the number thereon-,correspondinglto said angle 1s opposite the gaidel1ne2; t is is the only important operationneeded to operatel the course onlyw en all the parts ofthe drawing (card, crown) are in true relation to each other. Thisrelation is instantly visible without reading and is easy to maintain. The

pilot cankeep lhis course without strain and without having to yconsult the compass constantly. glance fromi time to time "aswith an or nary compass.- If its enable him to see course already set.

If the pilot has already set his compass and besides if he has noted on the border the residual deviations in the rectan ular spaces provided for this purpose, the ca culations will be greatly simplified. All he needs to do is to find on the map the angle of the true course, modiy said course according to the drift correction, then read opposite the correspondingligureV on the border, and finally tl? bring the guideline and said figure to- Oet er. aThe red areas 22 and 23 between'letters N and W further facilitate this reconstruction of the drawing especially at the start when the unsymmetry is greatest. Furthermore, the two letters R (right) and L (left) on the crown show which foot to use to re-establish the correct adjustment.

The two diagrams, Figures 6, 6, 7 and 7, show clearly the way to use these letters.

In Figure 6 the pilot deviates from his course to\the right. He reads on the crown the letter L opposite red area 23 on the card,

if he is flying along the presses the yleft foot-control, as in Figure 6,

smallest arc ,to vbe travelled is the one nearer letterL. He will then (press theleft foot control to maintain the a justment.

He would have operated inversely had the smaller arc been that of letter R.

In short no matter in what position the crown lies, that is, the ratio of the flyingi craft to the compass card 6, one myst always depress the foot-control ofthe side shown by the letter reached by the smallest arc.

If on the way the pilot. nds that the wind has changed and is causing drift, his an le of directlon can be modified by turning 51e knurled head of the worm.

In short the instrument has the following characteristics:

(1) Eliminates the reading of the anle of course, at a glance, even on dull days e Ipilot can ascertain whether he is flying to the course already set at the start.

(2) The wings, nose and tail of the schematicA airplane form four marksimpossible to confuse because outside their true relation they cannot be exactly assembled. So, whatever the pilots position is he will at least see two marks that will enable him to follow his set course.

(3) Graduations being on the border, the same compass may at the will of the operator be divided Ain degrees, grades or quadrants,

etc., simply by changing said border.

Incidentally, the vinvention allows to make,

While flying, all necessary corrections.

To set the 'de line, one proceeds exactly position d iffersbysay three then graduation 3 of said guide line is placed opposite the mark on the bowl and thus its exact positionwill be determined. All that need be done now is to tighten it by means of the screwv provided for this purpose and to proceed by the usual methods to the compensation proper of the compass.

The correction for declination is effected by moving the guide line one way or the other, according to the sign o1 the va`.ue of declination for the place considered; as for fixing d guide line, either the border or bowl graduations are used for this operation.

Having thus fully described the invention, what I claim as new and desire to protect by Letters Patent is:

l. A device for eliminating reading the angle of direction in navigation by compass, particularly for aircraft, comprising a rotatably mounted graduated bowl, an annular crown fixed inside said bowl, a compass card mounted within said crown, and a representation of the body of an airplane depicted on said card and having its corresponding nose, wing tips and tail positioned on said crown, whereby the parts of said representation are in alinement when the aircraft is on the proper course.

2. A device according to claim l further characterized by a fixed trame supporting said bowl, a graduated guide device carried by said frame, and means for setting the graduations on the bowl with respect to said guide device.

3. A device accor-ding to claim 1, further characterized by a fixed frame supporting said bowl, a graduated guide device carried by said frame, said device comprising a graduated plate slidable longitudinally on the frame and having an index co-operating with thec graduations of the bowl, an index member fixed to said frame opposite the graduations of the guide device, means for clamping said guide device in any position opposite the index member of the frame, and means for setting the graduations on said bowl with respect to the index of said graduated plate. 4. A device for eliminating reading the angle of direction in navigation by compass, particularly for aircraft, comprising a ro# tatably mounted. graduated bowl, an annular crown fixed inside said bowl, a compass card mounted within said crown, a representation of the body of an airplane depicted on said card and having its corresponding nose, wing tips and tail on said crown, whereby the parts of said representation are in alinement only when the aircraft is on the proper course, the sectors of the crown and compass card determined by one of the angles of said representation being brightly colored, the colored part of the crown bearing the letters-R and L, as an indicator in re-estab- Alisliing the course of the aircraft.

In witness whereof l have signed this specification.

Pinnen nscALLIEn. 

